Nano-chemical infrared imaging of membrane proteins in lipid bilayers

Reviews and Highlights	Quantum Science	Molecular and Soft-matter	Ultrafast Nano-optics and Nanophotonics	Mineralogy and Geochemistry

Samuel Berweger, Duc M. Nguyen, Eric A. Muller, Hans A. Bechtel, Thomas T. Perkins, and Markus B. Raschke
J. Am. Chem. Soc. 135, 18292 (2013).
DOI PDF SI

The spectroscopic characterization of bio-molecular structures requires nanometer spatial resolution and chemical specificity. We perform full spatio-spectral imaging of dried purple membrane patches purified from Halobacterium salinarum with infrared vibrational scattering-type scanning near-field optical microscopy (s-SNOM). Using near-field spectral phase contrast based on the Amide I resonance of the protein backbone, we identify the protein distribution with 20 nm spatial resolution and few-protein sensitivity. This demonstrates the general applicability of s-SNOM vibrational nano-spectroscopy, with potential extension to a wide range of biomolecular systems.

News: JILA Highlight